Many of the modules in this document define the required
attributes for their elements.
The elements in those modules also reference zero or more
attribute collections. Attribute collections are defined in their own
modules, but the meta collection "Common" is defined in this
section. The table below summarizes the attribute collections
available.

Note that while these Collections are referenced throughout
this document, these expressions should in no way be considered normative or
mandatory. They are an editorial convenience. When
used in this document, it is the expansion of the
term that is normative, not the term itself.

For the avoidance of doubt, if an attribute collection is referenced
by an element's definition, and an attribute in that collection is also explicitly
referenced by that element's definition, this does NOT cause a conflict. It is up to
the schema implementation to update the content models
accordingly.